Spanish to English Tech/Engineering Mechanics / Mech Engineering Packaging machine

Hi Everyone

I am translating part of the Spanish technical manual for a stretch hooding packing machine and it keeps referring to the "arrastres" and "desarrastres". For example

"Activa o desactiva los arrastres durante la bajada de los brazos"

"Esta opcion activa o desactiva el movimiento de la rueda de los arrastres"

"Tiempo de seguridad que transcurre entre que se activan los arrastres y empieza a girar el rodillo"

The only mention of desarrastres is:

"Sin Desarrastre abajo / Con Desarrastre Abajo: Esta opcion activa o desactiva los desarrastres"

I have spent three hours trying to find them, and reading websites about these machines, but I am still no clearer. I asusme it refers to moving the pallet into place and then removing it again but that is just a guess.

The translation is for tomorrow morning so any help people could give me today would be very appreciated.

Thanks

Penny